The present invention relates to electrical connectors, and more particularly to an interconnect device for electrically coupling a test instrument to a circuit board adapted for use with a ball grid array (BGA) connector.
BGA connectors are used in many applications where a low-profile, high-density electrical connector is desired or required. For example, circuit-board manufacturers often mount one or more BGAs on their circuit boards prior to shipping the boards to an intermediate or end user.
A typical BGA connector comprises a receptacle portion, and a plug portion adapted to mate with the receptacle portion. The plug and receptacle portions each include an insulative housing having a plurality of through holes formed therein. A plurality of male contact members positioned within the through holes of the plug portion, and a plurality of female contact members positioned within the through holes of the receptacle portion.
Each conducting member has a ball-shaped piece of solder material fixed to an end thereof. The balls of solder material protrude from the housing, and form a grid array on a surface of the plug or receptacle portions. The plug and receptacle portions are each mounted on a respective circuit substrate by aligning the respective grid arrays with a corresponding array of electrical contact points on a surface of the substrate. The solder balls are then reflowed to form a solder joint between each conducting member and a corresponding electrical connection point. These solder joints make it difficult to remove the plug and receptacle portions from the circuit substrate once the plug and receptacle portions have been mounted thereon.
The number of mating cycles for the plug and receptacle portions of a typical BGA conenctor, i.e., the number of times the plug and receptacle portions can be mated and unmated, is usually limited. For example, some types of BGA connectors commonly used on circuit boards must be discarded or reworked after approximately thirty to fifty mating cycles.
BGA-equipped circuit boards are usually subjected to functional checks prior to shipment. These checks are typically performed by interconnecting the circuit board to a test system via the BGA connector. More particularly, the receptacle (or plug) portion mounted on the circuit board is mated with a complementary plug (or receptacle) portion mounted on a circuit substrate of the test system. The substrate is electrically coupled to a test instrument. The test instrument is adapted to evaluate the functionality of the circuit board by sending electrical signals to the circuit board, and receiving and analyzing responsive signals therefrom.
A plug or receptacle portion used in a test system may be subjected to frequent mating cycles as circuit boards undergoing pre-shipment or research-and-development testing are repeatedly coupled and decoupled to and from the test system via the plug or receptacle portion. Such use can cause the plug or receptacle portion to reach the end of its useful life after a relatively short time period.
The above-noted difficulty in removing the plug or receptacle portion from its mounting surface usually necessitates replacement of the circuit substrate of the test system when the plug or receptacle portion mounted thereon reaches the end of its useful life. Replacing the circuit substrate on a relatively frequent basis can substantially increase the expense and time associated with the testing process. A need therefore exists for a device for interconnecting a test instrument to a circuit board adapted for use with a BGA connector, wherein the device can be used repeatedly without a need to replace or rework a circuit substrate of the corresponding test system.
A presently-preferred interconnect device for electrically coupling a test instrument and a circuit board having a first portion of a ball grid array connector mounted thereon comprises a pin header. The pin header comprises an insulative pin support member having a plurality of through holes extending between a first and a second surface thereof, and a plurality of terminal pins each positioned within and extending from a respective one of the through holes. The interconnect device also comprises a second portion of the ball grid array connector adapted to mate with the first portion. The second portion is mounted on the first surface of the pin support member and comprises a plurality of electrically conductive contact members each being electrically coupled to a respective one of the terminal pins.
The interconnect device further comprises a circuit substrate having a plurality of electrical connection points formed on a surface thereof and being adapted to be electrically coupled to the test instrument, and a socket receptacle mounted on the circuit substrate. The socket receptacle comprises an insulative receptacle support member having a plurality of through holes formed therein, and a plurality of pin receptacles each extending through a respective one of the through holes in the receptacle support member. Each of pin receptacles is adapted to removably receive a respective one of the terminal pins and is electrically coupled to a respective electrical connection point.
A presently-preferred system for electrically communicating with a circuit board having one of a plug portion and a receptacle portion of a ball grid array connector mounted thereon comprises a signal conditioning device adapted to send and receive electrical signals, and a substrate having a plurality of electrical connection points on a surface thereof. The electrical connection points are electrically coupled to the signal conditioning device. The system also comprises a pin header comprising an insulative pin support member and a plurality of terminal pins extending through and projecting from the pin support member.
The system further comprises a socket receptacle mounted on the circuit substrate and comprising an insulative receptacle support member and a plurality of pin receptacles extending through the receptacle support member. Each of the pin receptacles is adapted to removably receive a respective one of the terminal pins, and is electrically coupled to a respective one of the electrical connection points. The system also comprises the other of the plug portion and the receptacle portion of the ball grid array connector mounted on and electrically coupled to the pin support member.
A presently-preferred system for testing a circuit board having a first portion of a ball grid array connector mounted thereon comprises an interconnect device. The interconnect device comprises a pin header comprising an insulative pin support member and a plurality of terminal pins at least partially disposed within the support member. The interconnect device also comprises a second portion of the ball grid array connector adapted to mate with the first portion. The second portion is mounted on the pin support member and comprises a ball grid array and a plurality of contact members electrically coupled to the terminal pins via the ball grid array.
The interconnect device further comprises a circuit substrate having a plurality of electrical connection points formed on a surface thereof, and a socket receptacle mounted on the circuit substrate. The socket receptacle comprises an insulative receptacle support member and a plurality of pin receptacles at least partially disposed within the socket receptacle. Each of the pin receptacles is adapted to removably receive a respective one of the terminal pins and is electrically coupled to a respective electrical connection point. The system also comprises a test instrument electrically coupled to the circuit substrate and being adapted to generate and send electrical signals to the circuit board and to analyze responsive signals from the circuit board thereby evaluating the functionality of the circuit board.
A presently-preferred ball grid array connector system adapted for sub-surface mounting on a circuit substrate comprises a plug portion. The plug portion comprises an insulative housing having a plurality of through holes formed therein and extending between a first and a second surface thereof, and a plurality of male contact members each mounted in a respective one of the through holes. The system also comprises a receptacle portion comprising an insulative housing having a plurality of through holes formed therein and extending between a first and a second surface thereof, and a plurality of female contact members each mounted in a respective one of the through holes in the receptacle portion and begin adapted to removable engage a respective male contact member.
The system further comrises a pin header comprising an insulative pin support member having a plurality of through holes extending between a first and a second surface thereof, and a plurality of terminal pins each positioned within and extending from a respective one of the through holes in the pin support member. One of the plug portion and the receptacle portion is mounted on the pin header and each of the contact members of the one of the plug portion and the receptacle portion is electrically coupled to a respective one of the terminal pins.
A presently-preferred method for evaluating the functionality of a plurality of circuit boards each having a first portion of a ball grid array connector mounted thereon comprises mating a pin header with a complementary socket receptacle, and mating the first portion of the ball grid array connector with a complementary second portion of the ball grid array connector mounted on the pin header. The method also comprises directing electrical signals between a test instrument and the circuit board by way of the socket receptacle, the pin header, and the first and second portions of the ball grid array. The method further comprises removing and replacing the pin header and the second portion of the ball grid array after the second portion of the ball grid array connector has undergone a predetermined number of mating cycles.
A presently-preferred method of manufacturing one of a pin header and a socket receptacle comprises forming a plurality of through holes in a support member, the plurality of through holes being arranged in a plurality of rows and a plurality of columns. The method also comprises inserting a first plurality of conductive members in alternating ones of the through holes in each of the plurality of rows and in each of the plurality of columns. The method further comprises subsequently inserting a second plurality of conductive members in ones of the through holes adjacent the alternating ones of the through holes in each of the plurality of rows and in each of the plurality of columns.